The present inventors have developed N-acyl carbamate represented by the formula: ##STR1## wherein, R is hydrogen or a lower alkyl group and R' is a residual group obtained by removing a hydroxyl group from a monovalent alcohol; in Japanese Patent Laid-Open Publication No. 275259/1986, 275260/1986, 275270/1986 and 66563/1992, and also have developed the use thereof.
This N-acyl carbamate is prepared by reacting the compound which has the metal salt of an amide group represented by the formula: ##STR2## wherein, A is a 1-alkylvinyl group or an alkoxy group, and M.sup.+ is a metal cation; with the compound represented by the formula: ##STR3## wherein, X is halogen, and B is an alkoxy group or a 1-alkyl vinyl group; in an inert solvent, as described in Japanese Patent Laid-Open Publication No. 66563/1992. In this method, aprotic solvents such as a hydrocarbon, ether, ester, ketone, nitrile and the like, are exemplified as the inert solvent.
Japanese Patent Laid-Open Publication No. 279666/1990 discloses a method for producing an acyl carbamate in which an acid amide and a dicarbonate are reacted in the presence of a metal salt. 2-Butanol is exemplified as a solvent.
However, especially in case of producing N-methacryloyl carbamate, some problems may occur. For example, yield of the product decreases depending on a kind of the base compound used. When a metallic base is used as the base compound, the salt thereof with amide or the metal salt formed has low solubility in an organic solvent, and yield of the product extremely lowers. On the other hand, when an organic base is used as the base compound, the salt thereof is soluble in an organic solvent. However, N,N-dimethacryloyl carbamate is mainly produced, and an objective compound, N-methacryloyl carbamate is obtained in low yield.